Re: Image transference; was - archival ness of gum
----- Original Message ----- From: "Don Bryant" <email@example.com>
Sent: Friday, December 21, 2007 2:01 PM
Subject: Image transference; was - archival ness of gum
Here is a little anecdote I will share with you though I'm not sure it
falls in line with the same mechanism observed in the image transfer of
Once upon a time I routinely used yellow Post-It notes to identify sheets of
exposed film while I was on lengthy trips.
After returning from one such trip I was surprised to see the out line of
the Post-It note in the middle of an exposed sheet of 8x10 Tri-X after
processing. I was pretty blasé about the use of the Post-It notes and I
always put the note on the base side of the film. Apparently the Post-It
note image was transferred to the sheet beneath it on the emulsion side.
After that experience I quit the Post-It note practice.
Just some more food for thought.
Ryuji thinks this may be due to pressure on the emulsion but I suspect it may have been something in the paper that transferred, assuming the films and the paper were in contact for some time. Other things than light and pressure can cause silver halide to become developable.
Perhaps "permanence" is a better term than archivality or archivalness, which I think are not even valid words. There have been tests devised to determine permenance, at least for conventional silver-gelatin materials although they have been aimed mainly at materials like microfilm where long life is essential.
Permanence is not very meaningfull if the conditions the material is kept in are not defined. For instance, it is well known that high humidity and high temperatures are injurious to conventional materials. Also, resistance to attack by mold or insects is a separate issue from vulnerability to polutants from the atmosphere or from storage materials.
There is much literature pretaining to permanence relating to conventional B&W or color photographic materials but there is also research reported for computer generated prints using dyes or pigments. I think one can also find some material on conventional letter-press printing. At least some of this is available through such web sites as the Convervation On-Line site at
Stanford U., http://palimpsest.stanford.edu and at http://aic.stanford.edu/
I have no idea if any of the material at these sites is relavent to the current discussion but they are worth exploring.
Los Angeles, CA, USA